Solar heating effects often play a large part in the heating and cooling of building structures. Sunlight striking the external surfaces of a building may greatly increase the air conditioning load in the summer months. Conversely, solar heating effects may substantially reduce the heating load in the winter, particularly for small structures.
In order to control the effects of solar heating, many prior art devices have been used to reduce the heating effects of sunlight on internal building temperatures. Most designs involve the control of sunlight entering a building via the windows. For example, some designs involve coating the windows of a building with a light-reflective medium. This has the advantage of reflecting sunlight during the summer months and reducing the air conditioning load. This design is effective in buildings where a large amount of the surface area is transparent to sunlight. However, a problem exists with this design in that sunlight is also reflected during the winter months as well as the summer months. Thus, not only is the heating effect of the sunlight lost, but the interior of the building tends to remain dimly lit, requiring an additional energy expenditure for artificial lighting. Other schemes have been developed to control solar heating involving motorized blinds and shades. The blinds can be adjusted during the winter or summer months to adjust the amount of sunlight entering the building. However, this scheme tends to be complicated and expensive and becomes uneconomical if a large area must be controlled.
No method in the prior art has been developed in order to control solar heating effects over an entire surface of a building, including those portions which are opaque to sunlight.